• Declining species

• New alerts

• Positive changes

• Reduced breeding success

• Increased breeding success

• Early nesting

Declining species

Best trend estimates over the longest available time period (usually 38 years) provide alerts to rapid declines of 50% or greater for 22 species. These are Grey Partridge, Little Grebe, Woodcock, Turtle Dove, Cuckoo, Lesser Spotted Woodpecker, Skylark, Tree Pipit, Yellow Wagtail, Song Thrush, Whitethroat, Willow Warbler, Spotted Flycatcher, Marsh Tit, Willow Tit, Starling, House Sparrow, Tree Sparrow, Linnet, Lesser Redpoll, Yellowhammer and Corn Bunting.

Most of these rapidly declining species are already red or amber listed on the Population Status of Birds (PSoB) list (Gregory et al. 2002).

The Whitethroat decline results from the severe crash between 1968 and 1969 linked to conditions on the wintering grounds. The Little Grebe decline should be treated with caution as we have long-term data only from waterways.

Lesser Redpoll, Tree Pipit and Woodcock also have limited data. For several of the species listed here long-term trend data are only available for England, where BTO has more volunteers to record information. Different long-term trends could be operating in other parts of the UK.

A further 13 species trigger alerts as a result of long-term declines of between 25% and 50% over periods of 20 to 38 years. These are Red-legged Partridge, Kestrel, Lapwing, Redshank, Common Sandpiper, Little Owl, Tawny Owl, Meadow Pipit, Dunnock, Mistle Thrush, Reed Warbler, Lesser Whitethroat and Bullfinch. Most of these species are already on the PSoB list on account of their population declines.

Recent alerts and alert changes

We draw special attention to the alerts for three species that have recently crossed the 50% decline threshold. These are Yellow Wagtail (-70%), Willow Warbler (-60%) and Cuckoo (-59%). These may be candidates for future addition to the red section of the PSoB list.

We also identify four species that may become candidates to join the amber list due to declines of between 25% and 50%. These are Common Sandpiper (-26% over 25 years), Little Owl (-41% over 38 years), Tawny Owl (-27% over 25 years) and Lesser Whitethroat (-25% over 25 years). The two owl species are highlighted in this way for the first time. Red-legged Partridge also falls within this decline category (-30% over 25 years) but would not be a candidate for amber listing because it is an introduced species.

Bullfinch is a currently red-listed species, but its long-term population decline is now just under 50%, at -49% over 38 years, due to a population increase of 10% over the past 5 years. Similarly the red-listed Reed Bunting now shows only a 21% decline over the last 38 years, brought about by an increase of 27% over the past 5 years. If these trends continue both species may be candidates for changing from red to amber lists.

Reed Warbler populations monitored on reedbed sites have shown a population decline of -31% over the past 21 years. This is a worrying trend that needs further investigation.

Positive changes

Only a few of those species that have declined previously show evidence of improvements in status, with nine formerly declining species showing clear positive trends over the last 10 years. These are Red-legged Partridge, Snipe, Grey Wagtail, Dunnock, Song Thrush, Whitethroat, Goldcrest, Tree Sparrow and Reed Bunting. The increases in the red-listed Song Thrush and Reed Bunting are particularly encouraging, as are the positive trends for amber-listed Dunnock and Grey Wagtail. However the most recent figures for Song Thrush and Grey Wagtail suggest that their recoveries may be levelling off well short of their previous population levels. Similarly, while the BBS shows a 29% increase in Snipe over the last 10 years, the population has been declining again since 2003.

Eighteen species have more than doubled over the longest time period for which data are available (usually 38 years). These are Mute Swan, Canada Goose, Shelduck, Mallard, Goosander, Oystercatcher, Sparrowhawk, Buzzard, Stock Dove, Collared Dove, Woodpigeon, Green Woodpecker, Great Spotted Woodpecker, Nuthatch, Blackcap, Great Tit, Magpie and Carrion Crow.